(i) Field of the Invention
The present invention relates to an immunity test system for use in conducting an immunity test, i.e., an interference elimination ability test, to determine immunity of electronic equipment by using an interference wave.
(ii) Background Art
There has been a known immunity test to determine immunity of electronic equipment by using an interference wave, as one of EMC (Electro-Magnetic Compatibility) tests for evaluating electromagnetic compatibility of electronic equipment.
The immunity test is a test to determine whether or not electronic equipment as a test object (hereinafter also referred to as “test equipment”) can operate normally when irradiated with an interference wave. The frequency and the strength of the interference wave to be irradiated to the test equipment in the test are defined by international standards by, for example, the International Electrotechnical Commission (IEC), or by standards by a variety of organizations.
Accordingly, a system for conducting an immunity test is generally provided with a horn antenna having desired directional characteristics and an oscillator that inputs a transmission signal to the horn antenna to cause the horn antenna to emit a test wave as an interference wave. Before conducting a test, a signal level of a transmission signal to be input to the horn antenna by the oscillator is adjusted through an amplifier, an attenuator or the like, such that a test wave having a specified strength (for example, 600V/m) may be irradiated to test equipment. An example of such a system is disclosed in Publication of Unexanmined Japanese Patent Application No. 2003-121485.